High-Temperature Brazing of Superalloys and Stainless Steels with Novel Ductile Ni-Hf-Based Filler Metals

Nickel-based filler metals are generally used for brazing superalloys and high-alloyed steels to give joints with high-temperature resistance and corrosion resistance. The use of hafnium as a melting point depressant for nickel based filler metals instead of the conventional metalloids represents a metallurgical approach to produce ductile nickel brazing alloys with moderate brazing temperatures. Here the authors show that especially alloys of the system Ni-Hf-Cr possess suitable properties in terms of flowing and wetting behaviour on stainless steel and inconel 600. These new Ni-based filler metals are rollable and possesses high tolerances in terms of brazing gaps.